Background description includes information that may be useful in understanding the present invention. It is not an admission that any of the information provided herein is prior art or relevant to the presently claimed invention, or that any publication specifically or implicitly referenced is prior art.
Many rotating machines, such as motors, pumps, fans and the like, are connected to suitable ground supports via mounting assemblies. Such mounting assemblies are intended to absorb vibrations, but must also be capable of supporting weight of the machines and its dynamic forces during operation without getting excited at operating/forcing frequencies thereof (for example, due to variations in motor speed, load torque reaction, etc.). Design of such mounting assemblies is largely dependent upon nature and types of forces transmitted between the machine and the foundation.
Currently used investigation techniques for determining possibility of structural resonance of the mounting assembly excited by forcing operating frequency of a rotating machine are lengthy and intricate processes, and utilize analytical techniques such as bump test, finite element analysis, experimental modal analysis, operational deflection shape analysis, mode shapes plotting, etc. Such investigation techniques take a considerable amount of time particularly if the machines are installed at a remote location. Special tools such as, multi-channel vibration analyzer, instrumented hammer, etc., are also required to detect resonance and affected rigid body modes of support frame structures of the machines.
Once the affected rigid body modes, particularly rotational rigid body modes along x-axis and y-axis of the support frame structure and influencing operating frequencies of the machines are determined, modeling of the rigid body modes of the support frame structure using Finite Element based tools, simulation/modal testing of a structural modification of the mounting assembly is done to shift the resonant frequency of the mounting assembly away from the forcing frequency, and thereafter, modification of the mounting assembly is done by adding structural elements on the mounting assembly. Also, in order to alter structural modifications of conventional support frame structures, the machine and the support frame structure need to be dismantled and removed from their foundation.
There is therefore a need in the art to provide a mounting assembly for supporting a rotating machine to effectively prevent rigid body modes of the machine, particularly rotational motion along x-axis and x-axis. Further, there exists a need to provide for techniques to increase stiffness of the mounting assembly in a specific direction in order to prevent rotational modes of motion of the machine while the machine is installed on a foundation/structure at a site.
As used in the description herein and throughout the claims that follow, the meaning of “a,” “an,” and “the” includes plural reference unless the context clearly dictates otherwise. Also, as used in the description herein, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
In some embodiments, the numerical parameters set forth in the written description and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by a particular embodiment. In some embodiments, the numerical parameters should be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of some embodiments of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as practicable. The numerical values presented in some embodiments of the invention may contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
The recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g. “such as”) provided with respect to certain embodiments herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member can be referred to and claimed individually or in any combination with other members of the group or other elements found herein. One or more members of a group can be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is herein deemed to contain the group as modified thus fulfilling the written description of all groups used in the appended claims.